Is host age an important factor in the bionomics of Apanteles myeloenta (Hymenoptera: Braconidae)?

Hossein Kishani Farahani,Seyed Hossein Goldansaz

doi:10.14411/eje.2013.041

Abstract

The carob moth, Ectomyelois ceratoniae (Lepidoptera: Pyralidae), is a serious pest and causes a considerable loss of yield of pomegranate in Iran. Apanteles myeloenta (Hymenoptera: Braconidae) is the dominant parasitoid of this pest parasitizing it more than 30% in recent years. This parasitoid is a candidate for augmentative biological control program to reduce the level of the infes- tation of fruit overwinter. The objective of this research was to optimize the mass production of A. myeloenta. The mean develop- mental time of females was 28 days and of males 27 days. Pupal development lasted 7 days. The second instar was the preferred host and most heavily parasitized (45%). Wasps that started their development in second instar hosts produced the highest progeny and those that started in third instar hosts survived as adults for longest. The sex ratio (females to males) of A. myeloenta that emerged from carob moth larvae parasitized in the first instar was 1 : 3.5, in the second instar 1 : 3 and in the third instar 1 : 2. The influence of different host ages on the functional response of A. myeloenta to host density was assessed. Logistic regression indicated a type II functional response to different densities of all the stages of the host tested.

Highlights

The carob moth, Ectomyelois ceratoniae (Lepidoptera: Pyralidae), is of Mediterranean origin, but a cosmopolitan pest of pomegranate, pistachio, citrus, date, macadamia and fig crops (Gothilf, 1969, 1978; Alrubeai, 1987; Warner et al, 1990; Shakeri, 1993; Bouka et al, 2000; Mehrnejad, 2002; Nay & Perring, 2005; Blumberg, 2008)
To maintain the parasitoid stock culture, 30 mated female wasps were provided with about 900 second instar carob moth larvae for one day and females were transferred to 250 ml glass beakers, as egg laying units
Our results indicate that the maximum percentage of first, second and third instar hosts parasitized by A. myeloenta was 47.9%, 42.7% and 41.5%, respectively

Summary

Introduction

The carob moth, Ectomyelois ceratoniae (Lepidoptera: Pyralidae), is of Mediterranean origin, but a cosmopolitan pest of pomegranate, pistachio, citrus, date, macadamia and fig crops (Gothilf, 1969, 1978; Alrubeai, 1987; Warner et al, 1990; Shakeri, 1993; Bouka et al, 2000; Mehrnejad, 2002; Nay & Perring, 2005; Blumberg, 2008) It was recognized as the most economically damaging pest of pomegranate in Iran, where up to 80% of the fruit is damaged by this pest and is unmarketable (Shakeri, 2004), and the most economically damaging pest of the high value U.S date industry, causing 10–40% loss of yield annually (Warner, 1988; Nay et al, 2006). According to Kishani Farahani et al (2012a) A. myeloenta is a solitary, koinobiont (parasitoids whose larvae utilize a growing host), synovigenic (they emerge with some immature eggs and need to feed, to sustain egg production) endoparasitoid of the early instars of the carob moth. When their numbers are boosted by augmentative releases (Jervis et al, 2008; Kishani Farahani et al, 2012 a) it can cause a substantial decrease in the overwintering population of carob moth larvae

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Conclusion